I could say you could say he could say we could say you could say they could say
Forma con V-ing
I could be saying you could be saying he could be saying we could be saying you could be saying they could be saying
Perfecto
I could have said you could have said he could have said we could have said you could have said they could have said
Perfecto con V-ing
I could have been saying you could have been saying he could have been saying we could have been saying you could have been saying they could have been saying
Negación
Forma simple
I could not say you could not say he could not say we could not say you could not say they could not say
Forma con V-ing
I could not be saying you could not be saying he could not be saying we could not be saying you could not be saying they could not be saying
Perfecto
I could not have said you could not have said he could not have said we could not have said you could not have said they could not have said
Perfecto con V-ing
I could not have been saying you could not have been saying he could not have been saying we could not have been saying you could not have been saying they could not have been saying
Forma interrogativa
Forma simple
could I say? could you say? could he say? could we say? could you say? could they say?
Forma con V-ing
could I be saying? could you be saying? could he be saying? could we be saying? could you be saying? could they be saying?
Perfecto
could I have said? could you have said? could he have said? could we have said? could you have said? could they have said?
Perfecto con V-ing
could I have been saying? could you have been saying? could he have been saying? could we have been saying? could you have been saying? could they have been saying?
Forma interro-negativa
Forma simple
could I not say? could you not say? could he not say? could we not say? could you not say? could they not say?
Forma con V-ing
could I not be saying? could you not be saying? could he not be saying? could we not be saying? could you not be saying? could they not be saying?
Perfecto
could I not have said? could you not have said? could he not have said? could we not have said? could you not have said? could they not have said?
Perfecto con V-ing
could I not have been saying? could you not have been saying? could he not have been saying? could we not have been saying? could you not have been saying? could they not have been saying?